• Journal of the Korean Ceramic Society
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• v.47 no.5
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• pp.426-429
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• 2010

The Influence of the character of fly ash on the fluidity of cement paste with a polycarboxylic acid type superplasticizer was investigated in connection with the particle size distribution, unburned carbon content, specific surface area and shape of the fly ash. The fluidity of the fly ash cement paste with an added 20 vol% fly ash increases with an increasing roundness of the fly ash and it decreases with an increasing n-value of the fly ash cement. There is a linear correlation between the roundness/n-value and the fluidity of fly ash cement paste.

• Computers and Concrete
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• v.20 no.2
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• pp.197-204
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• 2017

Typically, high lime fly ash (Class C) has been characterized as a fly ash, which at lower replacement levels is not as effective as the low lime (Class F) fly ash, in mitigating alkali-silica reaction (ASR) in portland cement concrete. The influence of fineness of Class C, obtained by grinding virgin fly ash into finer particles, on its pozzolanic reactivity and ASR mitigation performance was investigated in this study. In order to assess the pozzolanic reactivity of mortar mixtures containing virgin or ground fly ashes, the strength activity index (SAI) test and thermo-gravimetric analysis (TGA) were conducted on the mortar cubes and paste samples, respectively, containing virgin fly ash or two ground fly ashes. In addition, to evaluate any improvement in the ASR mitigation of ground fly ashes compared to that of the virgin fly ash, the accelerated mortar bar test (AMBT) was conducted on the mortar mixtures containing different dosages of either virgin or ground fly ashes. In all tests crushed glass aggregate was used as a highly reactive aggregate. Results from this study showed that the finest fly ash (i.e., with an average particle size of 3.1 microns) could increase the flow ability along with the pozzolanic reactivity of the mortar mixture. However, results from this study suggested that the fineness of high lime fly ash does not seem to have any significant effect on ASR mitigation.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.91-96
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• 2002

본 연구는 화력발전소에서 발생하는 fly ash의 재활용 분야중 하나인 fly ash 경량골재 생산과정에서 소성(sintering)온도를 결정하는 미연탄소의 연소 현상을 분석함으로서 공정에 적용 가능한 단일 입자 연소 모델 개발을 목적으로 한다. fly ash 경량골재는 미연탄소를 포함한 fly ash를 점결제를 이용하여 성형하고, 함유된 미연탄소를 연소시켜, 그 연소열을 이용하여 fly ash를 소성 시켜 형성된다.(중략)

• Journal of Animal Environmental Science
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• v.5 no.1
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• pp.63-72
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• 1999

This study was carried out to improve utilization of fly ash. Each animal waste was mixed with fly ash and composted This compost used at forage crops with corn, rye and alfalfa to examine to examine the fertilized efficiency and investigated productivity of forage crops, composition of this copmost and effect of fly ash on soil characteristics and composition. Content of organic matte, P2O5, K2O, CaO, MgO, Mn and B at the soil, which is given fly ash, increased. After the test crops were harvested, pH of the soil was maintained about 7 and contents of organic matter, phosphoric aicd, K, Mg, and B was increased at the soil of used fly ash. As fly ash was mixed, each DM yield of corn and rye was increased 10∼13% and 14∼21% especially alfalfa was increased 35% at the soil which is mixed fly ash with cage layer manure. As fly ash was mixed, each Crude protein (CP) of corn and rye was increased 6∼17% and about 29%, especially, as fly and cage layer manure was mixed CP of alfalfa was increased 33%. In conclusion, as fly ash is mixed with anlmal waste and use at forage crops, It makes the soil good and improve the productivity of forage crops.

• Resources Recycling
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• v.5 no.3
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• pp.44-49
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• 1996

One of the most serious problems in utilizing the fly-ash produced from damcstic coal-firing power plants is lhc unburned-carbon mntained m the fly-ash In this shldy, the effects of fruther and collector an the yield,recuvery,unburnedcarbon rejectiou peiccntage,and process efficiency of product (cleaned fly-ash) wcrc examined when convzntional froth flotation was applied to rejcct the unburned-carbon included in the fly-ash of bituminous coal Alsa,the ash analysis for both thc raw and the clcaned fly-ash was conducted to review the change in thc major elements of fly-ash. Experimental results shawcd lhat tlle rcjectlon oI the unburned-cubon of thc raw fly-ash sample is available upto 92.4% using fiath flotalian and that the putity ol the pmdud(c1eancd fly-ash) attains up to 99.4%.

• Resources Recycling
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• v.19 no.2
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• pp.3-9
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• 2010

In most coal fired power plants, fly ashes collected from each of hoppers in the electrostatic precipitator are transported and stored in a silo. However the properties of the fly ashes collected from each of hoppers in electrostatic precipitator varies with the distance of the collection field from the boiler. The more distance hopper gets fly ash with larger specific surface area. Therefore, in electrostatic precipitator the hopper itself is expected to have the effect of classifying fly ashes. This study examines the physical, chemical and mineralogical properties of fly ash, collected from each of hoppers attached to an electrostatic precipitator in the coal fired power plant and looks into the possibility of the electrostatic precipitator being used as a classifier. Also, the study reviewed the possibility of acquiring high quality fly ash.

• Explosives and Blasting
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• v.21 no.2
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• pp.21-30
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• 2003

Currently, the shotcrete used as basic support in the tunnel excavation, has the advantages of maintaining high-level strength in condition of early shooting with thin thickness based on the excavation characteristics of rock mass. Therefore supreme equipment and materials were developed and the great strides have continued. Also, the development of measurement technology and the rocks behaviors of undergound are evaluated in detail and the designs of strength and thickness are made. The reinforcement materials development of new material is carried on. Most of the coal fly ash produced in Korea fire power plant is fly ash and bottom mash. Fly ash has been producing to be applied in many fields such as cement, aggregate, construction, civil, agriculture and fisheries. Also a lot of experiments are actively on the way. Therefore in this experiment, in order to use the fly ash mixed with concrete as a material of shotcrete, the experiment was performed in the best content to reduce the compression strength and the shooting rebound ratio of the excavated surface to use fly ash as a substitute material of concrete. As a result, when 15%.wt substitution was made to the fly ash, about 10% of compression strength and 6% of rebound ratio was reduced.

• Journal of the Korea Concrete Institute
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• v.11 no.6
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• pp.25-33
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• 1999

The role of fly ash in concrete become impotant with finding the charateristics of fly ash in which it is used as cement replacement material. An experimental study is carried out to investigate the characteristics of concrete containing fly ash. The loss of slump and air content of fly ash concrete tested up to 120 minutes are lower than those of ordinary concrete, but the setting time and bleeding are increased with increasing fly ash content. The compressive and tensile strength of fly ash concrete are slightly lower than those of ordinary concrete between 7 and 28 days, however, the long-term (at 180 days) compressive strength of fly ash concrete is significantly higher. In addition, fly ash reduces the heat of hydration and peak of temperature rise in concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.90-91
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• 2020

Utilization of upgraded fine fly ash in cement-based materials has been proved by many researchers as an effective method to improve compressive strength of cement based materials at early ages. The addition of fine fly ash has introduced dilution effect, enhanced pozzolanic reaction effect, nucleation effect and physical filling effect into cement-fly ash system. In this study, an integrated reaction model is adpoted to quantify the contributions from cement hydration and pozzolanic reaction to compressive strength. A modified model related to the physical filling effect is utilized to calculate the compressive strength increment considering the gradual dissolution of fly ash particles. Via combination of these two parts, a numerical model has been proposed to predict the compressive strength development of fine fly ash mortar considering fly ash fineness. The reliability of the model is validated through good agreement with the experimental results from previous articles.

• Journal of Animal Environmental Science
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• v.5 no.1
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• pp.37-44
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• 1999

This study was carried out to improve utilization of substitute fly-ash in bedding material of animal waste treatments. The amount used of fly-ash used in a pigpen or beef stall was 50% lower than that of existing bedding material of animal waste treatments. From the results, substitution effect of fly-ash put over the floor of the stable became much better. Effects of processed fly ash as a spread straw decreased ammonia(NH3) and Hydrogensulfide (H2S) gas at beef stall, but there was no benefit of replacement terms. Effect of processed fly ash as a spread straw increased 4∼5 times replacement terms more than control NH3 and H2S gas was decreased. A lot of maggots and porasites were grown at sawdust pig farm, but fly ash inhibited to grow maggots and paraeters. In conclusion, as substituting fly-ash for 5% sawdust(DM basis) in making animal waste into a compost with fly ash, we can reduce the sawdust purchasing costs and produce the high quality of a compost, especially a pollutant as NH3 and H2S gas, etc. from the process of biodegradation, and as substituting fly-ash(1,540 won per ton ; can be extended the replacement period of spreading straw approximatively 4∼5 times) for sawdusts(111,000 won per ton) will increase a real income in livestock house.